Desert dust aerosol columnar properties over ocean and continental Africa from Lidar in‐Space Technology Experiment (LITE) and Meteosat synergy

Abstract

[1] The new generation of spaceborne backscatter lidar systems, prefigured by the Lidar in-Space Technology Experiment (LITE) mission in September 1994, will give new insight on the vertical distribution of both aerosols and clouds in the atmosphere. This is especially of importance for aerosols over land, where retrievals from passive sensors are known to be more difficult because of the surface contribution. Here we analyze mineral dust aerosol transport events through a new approach coupling the active LITE and passive Meteosat-5 spaceborne observations. The Meteosat-derived aerosol optical thickness at 550 nm is shown to be a good boundary condition for the lidar inversion in order to retrieve both the aerosol backscatter to extinction ratio (BER) and the aerosol extinction vertical profile above the Tropical Atlantic Ocean (TAO) and the Mediterranean Sea. Sensitivity tests indicate that the aerosol scattering coefficient is retrieved within a 20% relative uncertainty. Air mass trajectories allow us to further retrieve the vertical profile of aerosol optical properties over the continent in the Saharan Heat Low (SHL) region using the BER determined over the ocean. Results confirm a large dispersion of the BER which is not attributed to errors in the method. This shows the need to account for such dispersion in the retrieval of dust aerosol optical thickness and aerosol impact on the earth radiative budget. The coupling between LITE and Meteosat-5 made here is shown to be interesting for an improvement of the direct dust aerosol forcing, and results should be improved by the CALIOP-MODIS synergy.

Aerosol vertical distribution and optical properties over M'Bour (16.96° W; 14.39° N), Senegal from 2006 to 2008

“…It corresponds also to a low (52 µg/m 3 ) PM 10 at the ground-level highlighting that most of the dust is transported in the aloft layer. Such vertical structure of the dust transport has also been observed by Berthier et al (2006) from the LITE spaceborne lidar over the Tropical Atlantic Ocean off the western African coast. Figure 11b presents the biomass burning aerosol profiles (SSA below 0.85).…”

Validation of CALIPSO space-borne-derived attenuated backscatter coefficient profiles using a ground-based lidar in Athens, Greece

“…LITE (Lidar Inspace Technology Experiment; McCormick et al, 1993), GLAS (Geoscience Laser Altimeter System; Spinhirne et al, 2005) and CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations; Winker et al, 2004Winker et al, , 2006Winker et al, , 2007) of atmospheric aerosols and clouds is the key for providing global vertically resolved observations that are needed to better understand a variety of aerosol-cloud radiationclimate feedback processes (e.g. Spinhirne et al, 2005;Berthier et al, 2006).…”

End-to-End Simulation for a Forest-Dedicated Full-Waveform Lidar Onboard a Satellite Initialized from Airborne Ultraviolet Lidar Experiments

“…The multiple scattering (MS) contributions are taken into account through the MS coefficient η [29], and depend on the wavelengths [66]. As previously explained (Section 2.2.3), this effect is negligible in UV (355 nm, η ≈ 1), but not in NIR (1064 nm, η ≈ 0.96).…”

“…These BER values were used in the following simulations and supposed constant in the canopy. Multiple scattering coefficient (η), at different depths in the scattering layer, is deduced from the ratio between the total lidar signal (including single scattering Ssingle and multiple scattering Smultiple) and the number of single-backscattered photon as [29]:…”